title: Torsional stability of a polished, collarless, tapered total replacement hip joint stem under vertical load: an in vitro investigation.
abstract: The torsional stability of a polished, collarless, tapered total replacement hip joint stem has been investigated. It was believed that such a stem would show increasing torsional stability as the vertical component of load on the stem increased. The aim of the study was to examine this hypothesis by testing a number of specimens (including Exeter stems) with either a matt or polished finish, under increasing vertical load, measuring the torsional resistance of a specimen-cement construct within an outer constrained cement shell. It was concluded that stems with a polished, collarless, tapered shape showed increased torsional stability with increasing vertical load, while stems with a matt finish or a collar did not.
authors.affiliation: Princess Elizabeth Orthopaedic Centre, Exeter, UK.
authors.forename: A
authors.initials: A
authors.lastname: Thomson
authors.forename: A J C
authors.initials: AJ
authors.lastname: Lee
mesh_terms: D001696:Biomechanical Phenomena; D001698:Biomedical Engineering; D006622:Hip Prosthesis; D006801:Humans; D066298:In Vitro Techniques; D011474:Prosthesis Design; D013499:Surface Properties; D054159:Torsion, Mechanical; D016474:Weight-Bearing